Multizone pusher-type furnace



Oct. 27, 1964 M. AMADIEU MULTIZONE PUSHER-TYPE FURNACE 3 Sheets-Sheet 1 Filed March 15, 1963 INVENTOR @2402; H/wd/ez ATTORNEY Oct. 27, 1964 M. AMADIEU MULTIZONE PUSHER-TYPE FURNACE 3 Sheets-Sheet 2 Filed March 15, 1963 FIG. 9

Get. 27, 1964 M. AMADIEU MULTIZONE PUSHER-TYPE FURNACE 3 Sheefs-Sheet 3 Filed March 15, 1963 INVENTOR 714.2014 flawd/ae ATTORNEY United States Patent 7 Claims. (or. 26336) The U.S. application No. 201,862, filed on June 12, 1962, and owned by the same assignee as the instant case, describes various improvements to multizone pusher-type furnaces for heating slabs or flat metal products.

In accordance with one of the particularities described in the U.S. application No. 201,862, the products are turned over, either inside a same furnace or between two distinct and complementary furnaces, at the end of the heating period and before the equalization zone, whereby to eliminate the black traces and the asymmetrical heating of the upper and lower faces of the products.

This invention relates more particularly to a device for turning over flat metallic products between two distinct multizone pusher-type furnaces.

If the turning over of the products externally to a furnace is to retain the advantages described in the U.S. application No. 201,862, it is necessary that the various operations to be performed between the heating furnace and the equalization furnace as will be described here inafter, be sufficiently rapid for the loss of calories resulting from the sojourn of the products outside the heating chamber to be negligible. In any event, this loss must not be greater than that which would have resulted from the provision of water circulating machinery within the furnace. In addition, as in the case of a single furnace, it is necessary that the transfer and turning over process from one furnace to the other take place without heavy knocks being sustained, so as not to mark the faces of the products at a time when they are very hot. Furthermore, it is desirable for the furnace drawing and charging operations not to interfere with normal, regular operation of the heating and equalization furnaces.

The present invention accordingly relates to the transfer and turning over of a slab or any other like metal product, from a heating furnace to an equalization furnace, under the required conditions of rapidity, absence of shocks and retention of normal operation of the furnaces.

In accordance with this invention, the transfer of the products under the required conditions is achieved by the combination of a charge drawing mechanism, a turning over mechanism and a double pusher, which various mechanisms are positioned between the two furnaces and operate in succession, being supplemented by a roller conveyor in cases where the longitudinal axes of the two furnaces do not coincide and/or by an elevator in cases where local conditions will not accept of the full drop in level between the charging point of the first furnace and the charge-drawing point of the second furnace.

The description which follows with reference to the accompanying drawing, which is filed by way of a nonlimitative example only, will give a clear understanding of the features hereinbefore described and will disclose still further particularities falling within the scope of the invention.

Referring to the drawing filed herewith:

FIGURE 1 is a schematic plan view of a complete installation for heating slabs and transferring the same between two complementary furnaces, embodying the particularities of the invention;

FIGURE 2 is a longitudinal section taken through the line IIII of FIGURE 1;

FIGURE 3 is a longitudinal section taken through the line III-III of FIGURE 1;

FIGURES 4 through 9 illustrate the successive relative positions of two sets of turn-over levers executed in accordance with the invention, during the operation of turning over a slab;

FIGURE 10 is a plan view of the relative dispositions of the various mechanisms positioned at the chargedrawing end of the heating furnace;

FIGURE 11 is a sectional view through the line XIXI of FIGURE 10, showing the turn-over mechanism in the inoperative position;

FIGURE 12 is a sectional view through the line XII- XII of FIGURE 10, showing the charge-drawing mechanism in the inoperative position; and

FIGURE 13 is a sectional view through the line XIII- XIII of FIGURE 12 of a lowering crab and a chargedrawing slideway forming part of the charge-drawing mechanism.

Reference is first had to the overall views of an installation according to this invention shown in FIGURES 1 to 3, in which numeral 1 designates a multizone pushertype heating furnace with frontal charge-drawing and cooled slideways, equipped with a turn-over mechanism as described in the U.S. application No. 201,862.

The chain-dotted lines illustrate an identical furnace 1', as it would be placed in a battery of several furnaces as indicated hereinafter. An equalization furnace 2, the longitudinal axis of which is offset relative to that of the heating furnace 1, is of the pusher-type with dry slideways and frontal charge-drawing. Chain-dotted lines are likewise used to represent a furnace 2' identical to furnace 2 and corresponding to the heating furnace 1' in the specific case where a battery of several furnaces is involved.

More generally, the installation is completed by a line of charging rollers 3 consisting of elements well known per se, by a line of transfer rollers 4 between furnaces 1 and 2, by a pusher 6 of known design for charging furnace 1, by a double-pusher 7 for charging furnace 2, by a mechanism 8 for drawing the charge from furnace 1, by a turn-over mechanism 9 and by an elevator 10 at the charging end of furnace 2.

Such an installation relates to the more general case of very wide furnaces capable of heating long slabs in a single row or half-length slabs in two parallel rows. In the course of all the successive operations except the final charge-drawing from the equalization furnace, halflength slabs are considered and handled in twos as if they formed a single long slab.

The charge-drawing mechanism 8 of furnace 1 is illustrated in greater detail in FIGURES 12 and 13. It com prises a number of slideways 11, four for instance, placed outside the furnace, which slideways form extensions of, and are sloped identically with, the cooled slideways of furnace 1. Said slideways are so profiled in section that their faces e serve to guide the slabs during the chargedrawing operation and their faces 1 and g to guide associated lowering crabs.

Each such crab (there being one per slideway) comprises a tubular body 12 provided with an articulation clevis 12a and a massive part 13 extended by a piston 13a which slides in the casting 12 and bears against a damping spring 14 or like elastic means. To each crab is associated a hydraulic actuator 15 which is pivotally connected to clevis 12a and displaces said crab along its slideway.

At the instant chosen for the charge-drawing operation, the terminal parts 13 of the crab are introduced into the furnace by the actuators 15, in the position shown in FIG- URE 2. In response to the action of pusher 6, the charge in heating furnace 1 moves along, While the slab which was ready to be drawn and initially occupied the position W in FIGURE 2, tilts over and comes into contact with the parts 13, this contact being damped by the springs 14. The crab terminal parts 13 are immediately withdrawn from the furnace by actuators 15. The slab, which on the one hand rested against the extremities of the moving parts 13 and, on the other, was guided by the faces e of slideways 11, accompanies the parts 13 and consequently descends the length of the slideways, after which it is drawn smoothly from the furnace and comes into position on the turn-over mechanism.

The hydraulic control equipment is so designed that actuators 15 be capable if necessary of absorbing any abnormal shock loadings (resulting, say, from the premature drop of a slab) the magnitude of which exceeds the normal absorption capacity of damping springs 14.

The slab turn-over mechanism shown in FIGURES 4 through 9 and 11 operates in substantially identical fashion to that described in detail in the US. application No. 201,862. Essentially it comprises a number of upstream levers 16, numbering four for instance, and downstream levers 17 equal in number to the upstream levers. The upstream levers 16 are specially shaped and embody in particular a heel d. Said levers are supported on a shaft 16a and, in the inoperative position, their principle axis k is set at an angle [3 which is slightly less than the angle a of the sliding plane formed by the faces e of slideways 11.

The downstream levers are similarly shaped to the upstream levers and are mounted on a shaft 17a. Said levers are provided with a heel d which additionally serves as means'for guiding the slabs while they are being conveyed along the transfer rollers 4. In the inoperative position, that face of the downstream levers which is parallel with their principal axis l is horizontal and positioned at a distance a below the upper plane tangential to rollers 4.

Levers 16 and 17 are combined in two groups supported upon a structure 21. The pivotal motions of the lovers are ensured by a linkage 18 and levers 19 rigid with control shafts 20. Said shafts 20 are in turn rotated by any convenient mechanism (not shown) which may be of the hydraulic or mechanical type and upon which devolve, in all cases, the function of ensuring the necessary successive movements whereby the slab turn-over cycle which will now be described may be accomplished.

In an initial stage (see FIGURE 4), downstream levers 17 pivot from the resting position in the direction of arrow F1. During this time, the slab or like product sliding along face e of slideway 11 is deposited by the lowering crab upon the heel d of upstream levers 16.

During the second stage (FIGURE after pivoting through an angle of about 100, levers 17 stop in the position shown in FIGURE 5, i.e. a few degrees past the vertical. As soon as product 0 has been deposited on the heels d of levers 16, said levers pivot in the direction of arrow F2 to meet levers 17.

During the third stage (FIGURE 6), when levers 16 reach a position parallel with that reached by levers 17 during the second stage, their motion is halted. The faces of the upstream and downstream levers are then spaced apart by a distance b slightly greater than the thickness of product c. If desired, steps could be taken for the spacing b to be variable and adjustable according to the thickness of the product 0, thereby ensuring a minimum clearance between the levers and the slabs regardless of the thickness of the slabs 6.

The two levers then immediately begin to pivot together in the same direction, namely in the direction of arrow F2 which is the pivoting direction of levers 16 during the second stage, in such manner that the spacing 17 remain substantially constant throughout the joint motions of the upstream and downstream sets of levers.

During the fourth stage (FIGURE 7), the slab moves from one set of levers to the other, for up to that point the product c was resting upon the heels d of upstream levers 16. When the vertical position is reached, the heels d of downstream levers 17 contact the point While the heels d of upstream levers 16 retract. Thus the transfer from one set of levers to the other, takes place smoothly and without the slabs dropping.

During the fifth stage, when the two sets of levers reach the position shown in FIGURE 8, namely the position symmetrical to the position of FIGURE 6 with respect to the vertical, the motion of upstream levers 16 is reversed and said upstream levers follow arrow F1 towards their resting positions while downstream levers 17, which still carry the product 0, continue to pivot in the same direction F2.

During the sixth stage (FIGURE 9), the product c is deposited smoothly, after it has been turned over upon the train of transfer rollers 4. The upstream and downstream levers are halted in the resting positions at the end of this ultimate operation, the initially upper face of the slab now becoming the lower face.

As will be well understood by the specialist in the art, the roller conveyor 4 can utilize either a combined form of roller drive or an individual drive for each roller. As shown in FIGURES l0 and 11, the conveyor is preferably of the latter type, and numeral 4a thereon schematically illustrates the individual drive associated to each roller. Such an arrangement allows for controlling the rollers of a plurality of sections individually, whereby to ensure, regardless of whether a single long slab or two half-length slabs are being conveyed, correct positioning of the products conveyed with respect to the axis of equalization furnace 2, such control being governed for instance by a system (not shown) of electro-magnetic contacts, photoelectric cells or like detection means.

The function of elevator 10 is to compensate, partly or entirely, for the supplementary drop in level resulting from the intermediate charge-drawing required by the very design of the installation, and to ultimately preserve under the conditions customarily found in furnaces resorted to hitherto, the total drop in level between the primary charging point and the final charge-drawing point. Said elevator offers the additional advantage of making it possible to use conventionally constructed conveyor rollers since it enables same to be positioned below the furnace threshold and to be consequently sheltered from the heat.

Such an elevator could nonetheless be dispensed with if local conditions will absorb the total drop in level between the primary charging point and the final chargedrawing point; in such cases, however, since the hearth of furnace 2 would be lowered to the level of rollers 4, the latter would have to be specially constructed. Said elevator is mechanically or hydraulically operated and suitable stops ensure that it is accurately positioned with respect to the plane of the hearth of furnace 2.

The double-pusher 7, the purpose of which is to charge furnace 2, incorporates a number of special features which fall within the scope of this invention and which enable it to be used with the rapidity of operation and preservation of the normal furnace operating conditions required by the present invention. More particularly,

the pushing members in the example on FIGURE 1 consist of four water circulating pusher tubes 22 which are supported in pairs by a shield 23 fitted with the mechanism 24 of each pusher proper.

The two pushers can be coupled or uncoupled according as the furnace charge consists of long slabs or halflength slabs.

In addition, the door of furnace 2 is provided with notches for passage of the pusher tubes 22 through the door. This arrangement of pusher tubes and notches in the furnace door permits to shut the door immediately after the slab has been transferred from the position X in FIGURE 3 into furnace 2 (position Y). The push on the total charge in furnace 2, which causes discharging to take place, can then be pursued immediately, or on the contrary deferred with the door kept shut, depending on the demand from the rolling mill for which the slabs are destined.

The thrusting operation thus includes two distinct suc cessive operations:

1) A high-speed stroke effected with the door open, enabling a long slab or two half-length slabs to be introduced rapidly from position X to position Y in FIG- URE 3.

(2) A low-speed stroke effected with the door shut, enabling the entire furnace charge to be pushed along and causing the last slab to be shifted from position Y to position Z in FIGURE 3. The two pushers can accomplish this part of the stroke simultaneously if the furnace is charged with long slabs, or in succession if the furnace is charged with half-length slabs. Since this part of the pusher stroke corresponds to the drawing of a slab ready for rolling, the half-length slabs that have hitherto handled in pairs like a single long slab can consequently be drawn one by one.

After the charge-drawing operation, the pushers revert to their resting positions, the charging door still remaining shut.

It will be seen, therefore, that the charging door remains open only for the very short time required to introduce a slab into the furnace, and also that the charging and charge-drawing doors are never opened simultaneously a vital requirement for uniform operation of the furnace.

It will also be seen that the operations whereby a slab is turned over and transferred from the position W of furnace 1 (FIGURE 2) to the position Y of furnace 2 (FIGURE 3) are pursued without interruption, hence rapidly, and that the final charge-drawing is independent of these operations and can keep pace with rolling mill demand without delay.

Although the axis of heating furnace 1 is offset relative to the axis of equalization furnace 2 in the particular example described precedingly, as may be clearly seen in FIGURE 1, the siting of a battery comprising a plurality of furnaces does not require a greater number of building bays than an installation consisting of conventional furnaces, for the equalization furnaces 2, 2, etc., are located in the extensions of the normal intervals required between two heating furnaces 1, 1', etc.

In addition, in this specific disposition, the lowering turn-over, roller, pusher and other mechanisms are easily accessible beyond the area occupied by the furnaces, and affect neither construction, operation or maintenance of same.

However, this particular disposition, cited by way of a non-lirnitative preferred example, by no means excludes any other convenient position, featuring for instance two furnaces positioned upon a common axis with the tumover and transfer devices placed between the two furnaces; with such an arrangement, the train of conveyor rollers would be dispensed with and the recharging device would be provided beneath one of the furnaces, the design of which would be suitably modified accordingly.

What is claimed is:

1. A multizone pusher type furnace arrangement for heating slabs, flat ingots or the like products comprising, in combination, elongated conveyor means; a heating furnace located at one side of said conveyor means and having a longitudinal axis extending transverse to the longitudinal direction of said conveyor means, said heating furnace having a discharge end facing said conveyor means; an equalization furnace located at the other side of said conveyor means and having a longitudinal axis offset with respect to the axis of said heating furnace and extending transverse to the longitudinal direction of said conveyor means, said equalization furnace having a receiving end facing said conveyor means; a charge drawing means extending substantially aligned in direction of said longitudinal axis of said heating furnace from the region of said discharge end thereof toward said conveyor means for receiving a slab or like product discharged from said heating furnace and for guiding the same toward said conveyor means; turnover means in the region of said charge drawing means for receiving the slab or like product from said charge drawing means and for depositing said slab in inverted position on said conveyor means; and a double pusher substantially aligned with the longitudinal axis of said equalization furnace and facing said receiving end thereof for transferring the slab from said conveyor means into said equalization furnace.

2. A furnace arrangement as set forth in claim 1, wherein said conveyor means is arranged at a lower elevation than said discharge end of said heating furnace and wherein said charge drawing means includes means for damping the fall of a slab or the like product or any abnormal shocks sustained thereby, and for depositing said product in the required position on said turnover means.

3. A furnace arrangement as set forth in claim 2, wherein said charge drawing means includes a plurality of slide ways extending from said discharge end of said heating furnace downwardly inclined into the region of said conveyor means and having each a guide face for guiding a slab or like product on its downward movement from said discharge end of said heating furnace toward said conveyor means; a lowering crab on each slide way and including said damping means; cooperating guide means on said slide ways and said crabs for guiding the latter in longitudinal direction of said slide ways; and actuator means connected to said crabs for moving the same along said slide ways.

4. A furnace arrangement as set forth in claim 3, wherein each of said lowering crabs includes a cylinder guided on the respective slide way; piston means having one end facing said discharge end of said heating furnace and extending beyond one end of said cylinder toward said discharge end; and spring means in said cylinder and connected to said piston means for yieldably maintaining said one end of said piston means spaced a predetermined distance from said one end of said cylinder.

5. A furnace arrangement as set forth in claim 3, wherein each of said slide ways is cooled.

6. A furnace arrangement as set forth in claim 3, wherein said conveyor means comprises a plurality of spaced rollers, and wherein said turnover means comprises a first set of heeled levers located in the region of said slide ways and having each a rest position in which an upper major surface of each lever is located in substantially one plane with said guiding face of said slide ways, and a second set of heeled levers located respectively between said rollers and having a rest position in which an upper major surface thereof is located substantially in one plane with the uppermost generatrices of said rollers, said two sets of heeled levers being turnable from said rest position about parallel adjacent pivot axes for swinging a slab or the like product through an arc from said guide face on said slide ways onto said rollers while the same remains engaged by said levers 'so as to transfer the slab or the like product in a shock free manner from said slide ways onto said rollers of said conveyor means.

7. A furnace arrangement as set forth in claim 1, wherein said conveyor means comprises a plurality of spaced rollers; and individual drive means for each of said rollers at least in the region of said receiving end of said equalization furnace.

References Cited in the file of this patent UNITED STATES PATENTS Herrick July 7, 1903 Ferm Nov. 18, 1924 Weidner et a1. Jan. 27, 1942 Passaforo Dec. 2, 1952 McCoy Feb. 18, 1958 Ferguson Apr. 21, 1964 

1. A MULTIZONE PUSHER TYPE FURNACE ARRANGEMENT FOR HEATING SLABS, FLAT INGOTS OR THE LIKE PRODUCTS COMPRISING, IN COMBINATION, ELONGATED CONVEYOR MEANS; A HEATING FURNACE LOCATED AT ONE SIDE OF SAID CONVEYOR MEANS AND HAVING A LONGITUDINAL AXIS EXTENDING TRANSVERSE TO THE LONGITUDINAL DIRECTION OF SAID CONVEYOR MEANS, SAID HEATING FURNACE HAVING A DISCHARGE END FACING SAID CONVEYOR MEANS; AN EQUALIZATION FURNACE LOCATED AT THE OTHER SIDE OF SAID CONVEYOR MEANS AND HAVING A LONGITUDINAL AXIS OFFSET WITH RESPECT TO THE AXIS OF SAID HEATING FURNACE AND EXTENDING TRANSVERSE TO THE LONGITUDINAL DIRECTION OF SAID CONVEYOR MEANS, SAID EQUALIZATION FURNACE HAVING A RECEIVING END FACING SAID CONVEYOR MEANS; A CHARGE DRAWING MEANS EXTENDING SUBSTANTIALLY ALIGNED IN DIRECTION OF SAID LONGITUDINAL AXIS OF SAID HEATING FURNACE FROM THE 